Since 1982, a newly classified bacteria, Campylobacter pyloridis (C. p.) has received a great deal of attention, as to the role it plays as a causative agent in the development of gastroduodenal disease in man. Several clinical studies have confirmed C. p. and its association with gastritis, and in some cases peptic ulcer disease. However, the exact role of C. p. in development of gastroduodenal disease requires further study. In collaboration with scientists at B.U. Medical School, we intend to study select patient populations on a longitudinal basis. Studies are designed to monitor the presence of C. p. in gastric mucosa of patients, over time, by the use of bacterial restriction endonuclease analysis (BRENDA) of C. p. and to monitor host immune response to the infection with ELISA and Western blot methods. In addition, we intend to develop animal model systems that simulate human infection and with these models study the pathogenesis of the disease.